I love to bit seeing very old barn trucks start again, very rough sounding engine lots of grunt and coughing. No matter how good you let it warm up again it will never sounds smooth and powerful again. Often takes a lot longer to startup and the performance is decreased. A bit more pollution from the exhaust pipes. The Idea is to create a configuration engine for the T-series that represents this condition. We don't want the T-series engine config to shoot out smoke from all places, just more pollution from the exhaust pipes. See video example bellow
I think with a bit of tooling around with emitters and maybe some Lua it could be done, but I'm too high and too stupid to do this myself. Probably a T-65 with like a beater T-200 turbo or something like that, maybe some classic wheels and different lights for an older look.
Make the starter less effective, tweak the soundconfig, increase the idleRPMroughness, increase the particulates. I could maybe whip up one later...